I was hand weeding today when one small weed fought back. I normally wear gloves but was just casually pulling a few barehanded while waiting for someone in the front yard. The stem of this plant was covered in tiny tiny thorns. Normally a thorn hurts for only a few seconds but this hurt so much I had to go in the house and wash. But the water made it feel worse. I looked carefully for embedded thorns but found none. It gradually went away after a few hours but hurts all over again every time I wash my hands. ItÂs more like a burning sensation than being pricked.

What is this and what can I do if I encounter this plant again glove-less? There was nothing distinctive about the way this plant looked apart from being thorny all over, even the leaf stems.